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对取自重庆地区的不同粒度的砂岩进行单轴压缩条件下的声发射试验,并以时间为参考变量,得到力学与声发射参数之间的耦合关系,对其进行分析研究,以研究粒度对砂岩在单轴压缩破坏过程的影响规律,并以此进一步揭示岩石破坏的微观机制,结果表明:(1)粒度越大,砂岩的抗压强度越大,弹性模量越大,峰值应变越小。表明粒度越大,砂岩的抗压和抗变形能力越强。(2)砂岩的声发射现象可以分为三个阶段:初始压密期、平静期和爆发期。粒度对砂岩的声发射初始压密期和平静期影响不明显,但对爆发期有显著影响,粒度越大,砂岩在破坏阶段的声发射越剧烈。(3)从砂岩声发射RA值可以看出,砂岩破坏时的裂纹为张剪混合裂纹,以剪切裂纹为主,粒度越大,张拉裂纹越多。并且砂岩声发射RA值在破裂发生前都有突然增大,并达到峰值的现象,预示着破裂即将发生,因此可以将声发射RA值的突然增加作为砂岩破裂前兆信息。。
The acoustic emission tests under different uniaxial compression conditions for sandstones with different particle sizes from the Chongqing area were carried out. Using the time as the reference variable, the coupling relationship between the mechanical and acoustic emission parameters was obtained and the analysis was performed to study the particle size pair. The effect of sandstone on the failure process under uniaxial compression and further reveals the micromechanism of rock failure. The results show that: (1) The larger the grain size, the greater the compressive strength of sandstone, the greater the elastic modulus, and the smaller the peak strain. . It shows that the greater the grain size, the stronger the compressive and deformation resistance of sandstone. (2) The acoustic emission phenomenon of sandstone can be divided into three stages: initial compaction period, quiet period and outbreak period. Particle size has little effect on the initial compaction period and quiet period of acoustic emission of sandstone, but it has a significant impact on the outburst period. The larger the grain size, the more severe the acoustic emission of sandstone during the destruction stage. (3) From the RA value of sandstone acoustic emission, it can be seen that the cracks in sandstone failure are shear-shear mixed cracks, mainly shear cracks, the larger the grain size and the more tensile cracks. And the RA value of sandstone acoustic emission has suddenly increased before the rupture occurred, and the phenomenon of peak value indicates that the rupture is about to occur. Therefore, the sudden increase of acoustic emission (RA) value can be used as a precursor to sandstone rupture. .